NASA is set to launch the world's first mission devoted to studying rapidly spinning neutron stars, the densest objects in the universe.The agency plans to launch the two-in-one Neutron Star Interior Composition Explorer, or NICER, aboard SpaceX CRS-11, a cargo resupply mission to the International Space Station to be launched aboard a Falcon 9 rocket.About a week after its installation as an external attached payload, this one-of-a-kind investigation will begin observing neutron stars, the densest objects in the universe. The mission will focus especially on pulsars — those neutron stars that appear to wink on and off because their spin sweeps beams of radiation past us.